The Child Health and Mortality Prevention Surveillance (CHAMPS) project aims to inform policies to prevent child deaths by adjudicating causes of death among children under-five years of age in high-mortality countries. As such, a key objective of CHAMPS is to define population-based rates for causes of death through diagnostic and laboratory methods nested within population surveillance. The CHAMPS Health and Demographic Surveillance Systems Network provides the population platform for estimating rates and understanding contextual factors.. The six HDSS sites in the Network are in Mozambique, Mali, Ethiopia, Kenya, Bangladesh, and South Africa, with new sites being established in Sierra Leone and India. I will describe the CHAMPS minimally-invasive tissue sampling method, the HDSS Network, and early results from these efforts to more precisely characterize causes of death among young children.